Publications in the form of electronic books, i.e. electronic publications, have begun to be actively performed in place of publications produced by conventional printing techniques in association with the spread of electronic information networks. For example, cathode ray tube (CRT) displays and back light type liquid crystal displays are generally used as devices to display electronic information distributed through such networks. The displays using these displays have, however, a limitation in places where the displays are read, and the displays are also inferior in their handling in terms of weights, sizes, shapes, and portability, in comparison with the common displays printed on sheets of paper. Furthermore, because these displays consume large electric power, the displays also have a limitation on their display times in the case where the displays are driven by batteries. Furthermore, all of these displays are light emitting type displays, and consequently they also have a problem of causing severe fatigue at the time of a long time gaze.
Accordingly, a display device or a rewritable display device capable of resolving the aforesaid problems has been desired. A device called a paper-like display or electronic paper has been proposed as such a display device. To put it concretely, for example, a display device of a reflective liquid crystal system, a display device of an electrophoresis system, a display device of a system of rotating dichromatic particles in an electric field, a display device of an electrochromic system (see, for example, Patent Documents 1 and 2), and the like have been proposed in the past.
Now, in the display device of the electrochromic system (electrochromic display device), for example, an electrochromic composition containing a dye precursor, such as a leuco dye, which colors on the surface of an electrode, as an essential ingredient is used as a display material. The leuco dye is a superior material as an electrochromic material because the leuco dye is versatile as a recording material for thermal recording and the like and consequently can be easily obtained and procured, and because there is a possibility that the leuco dye is capable of displaying each color.